Despite all the negativity around the future for the Qantas fleet, I believe there may still be some surprises around the corner. Which in turn may lead to more pilots being hired (if these aircraft are crewed by mainline pilots).
The 789 is an extremely viable option for mainline, specifically for Australia-Asia, Perth (Bris,Adel) - Dubai, and also Pacific routes.
The rumoured low acquisition price of these aircraft make them a very attractive whether that be through a purchase outright or if capital constrained, on sell to leasing companies for a profit then leasing back.
Secondly, there is a possibility of mainline operating rumoured fleet of 25 A320/321. With a group order for 110 odd A320 and a distinct possibility that Jetstar Hong Kong with fly the same amount of services as RedQ, the aircraft have to go somewhere.
QF were close to an order of A320 prior to Sept 2001 for mainline ops, however a very attractive deal for B738 came about when American Airlines had a sudden excess of 75 NG's on order and QF needed metal fast due to the demise of Ansett.
The NEO's become available early 2016 and A321Neo's would be a perfect fit to replace B767 on golden triangle and off peak Perth routes.
Additional advantages of A321Neo's for mainline is capacity increase over B738 & existing A321, also aerobridge access to 2 forward doors, streamlining turn around and giving premium pax the advantage of boarding separately or turning left on entry.